Air compressors

ABSTRACT

An air compressor may include a compressor unit and an external tank unit connectible with the compressor unit. The external tank unit may include an external tank and a battery. The battery may supply electric power to the compressor unit.

This application claims priority to Japanese patent application serialnumber 2011-254731, the contents of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the present invention relate to air compressors that maybe used, for example, for supplying compressed air to pneumatic tools,such as nailers and tackers that can be driven by compressed air.

2. Description of the Related Art

There have been provided simplified air compressors. Simplified aircompressors may have smaller discharge outputs than stationarylarge-sized air compressors. However, because simplified air compressorsare light and small and can be easily carried about, they can beconveniently used when performing simple and light duty work involvingpneumatic tools. U.S. Pat. No. 7,140,845 and JP-A-2-108878 teachtechniques relating to simplified air compressors that have batteries(DC power sources) as power sources.

The simplified air compressors disclosed in the above documentstypically have an electric motor and a compressing device that aredisposed within a resin case. The compressing device may convert therotational output of the electric motor into a reciprocating movement ofa piston within a cylinder for discharging compressed air. Thecompressed air discharged from the compressing device may be directlysupplied to a pneumatic tool. Therefore, the air compressor can belightweight because there is no need for a storage tank for storing thecompressed air.

In addition, the user may carry the simplified air compressor on his orher shoulder or back. Therefore, it is possible to supply the compressedair to a pneumatic tool, such as a nailer, at a place, such as abuilding site, where no electric outlet is available. Hence, there wouldbe no restriction with respect to the place for use. In this way, it ispossible to efficiently perform light duty works, such in the repairingof items or structures.

JP-A-2006-220202 teaches a technique of providing an external auxiliarytank at an AC powered air compressor that is relatively small in sizebut is of a stationary type having an internal storage tank. Byproviding the external auxiliary tank, it may be possible to stablysupply a larger output of compressed air.

The air compressors disclosed in the above documents still requireimprovements. For example, if an external auxiliary tank is connected tothe battery driven air compressor for supplying a larger output ofcompressed air, a larger electric power is necessary to be supplied bythe battery. In this case, it may be possible to cause lack of residualpower in the battery. For this reason, it is necessary to frequentlyrecharge or replace the battery. As a result, it is necessary tofrequently stop the work, leading to low productivity.

Therefore, there has been a need in the art for a technique for fixingthe lack of power in an air compressor that results when an externaltank is used.

SUMMARY OF THE INVENTION

In one aspect according to the present teachings, an air compressor mayinclude a compressor unit and an external tank unit connectible with thecompressor unit. The external tank unit may include an external tank anda battery, The battery may supply an electric power to the compressorunit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing the configuration of an air compressoraccording to a first embodiment, in which a pneumatic tool is connectedto an external tank unit;

FIG. 2 is a diagram showing the configuration of an air compressoraccording to a second embodiment, in which a pneumatic tool is connectedto a compression unit; and

FIG. 3 is a diagram showing the configuration of an air compressoraccording to a third embodiment, in which a compression unit isschematically shown.

DETAILED DESCRIPTION OF THE INVENTION

Each of the additional features and teachings disclosed above and belowmay be utilized separately or in conjunction with other features andteachings to provide improved air compressors. Representative examplesof the present invention, which examples utilize many of theseadditional features and teachings both separately and in conjunctionwith one another, will now be described in detail with reference to theattached drawings. This detailed description is merely intended to teacha person of skill in the art further details for practicing preferredaspects of the present teachings and is not intended to limit the scopeof the invention. Only the claims define the scope of the claimedinvention. Therefore, combinations of features and steps disclosed inthe following detailed description may not be necessary to practice theinvention in the broadest sense, and are instead taught merely toparticularly describe representative examples of the invention.Moreover, various features of the representative examples and thedependent claims may be combined in ways that are not specificallyenumerated in order to provide additional useful examples of the presentteachings. Various examples will now be described with reference to thedrawings.

In one example, an air compressor may include a compressor unit and anexternal tank unit. The compressor unit may supply a compressed air to apneumatic tool. The external tank unit may be connectible with thecompressor unit. The external tank unit may include an external tank anda battery. The external tank may store the compressed air. The batterymay supply an electric power to the compressor unit.

Therefore, when the external tank is connected to the compressor unitfor enabling the compressor unit to supply a larger output of compressedair to the pneumatic tool, it is possible to supply electric power tothe compressor unit from the battery of the external tank unit. In thisway, it is possible to supply a larger output of compressed air to thepneumatic tool without causing a lack of electric power for driving thecompressor unit. As a result, it is possible to avoid interruption ofthe work performed by the pneumatic tool. Therefore, productivity can beimproved.

The compressor unit may include an air-compressing device and a batteryserving as a power source for driving the air-compressing device. Withthis arrangement, it is possible to use the air-compressing device at aplace where no AC power source is available. In this way, theworkability can be improved. In addition, the battery of the externaltank unit and the battery of the compressor unit can be usedsimultaneously or exchangeably for driving the air-compressing device.

In the case where the battery of the external tank unit and the batteryof the compressor unit are interchangeably used for driving theair-compressing device, one of the batteries can be recharged orreplaced with another battery during driving of the air-compressingdevice by the other battery. Therefore, it is possible to operate theair-compressing device continually for a long time in a manner similarto the case where an AC power source is used.

The external tank unit may include a battery charger capable of chargingthe battery of the external tank unit. With this arrangement, it ispossible to charge the battery of the external tank unit without needingto remove the battery from the external tank unit. Therefore, theoperability of the air compressor can be improved.

The external tank unit may be configured to be able to connect anelectric device that is a different device from the compressor unit, sothat electric power can be supplied from the battery of the externaltank unit to the electric device. In this way, it is possible to furtherimprove the usability of the external tank unit and the air compressor.

The battery of the external tank unit may be removably mounted to theexternal tank unit. With this arrangement, it is possible to replace thebattery with another battery or to recharge by a separate batterycharger.

Embodiments will now be described with reference to FIGS. 1 to 3.Referring to FIG. 1, there is shown an air compressor 1 according to afirst embodiment. The air compressor 1 may generally include acompressor unit 10 and an external tank unit 30 connected to thecompressor unit 10. The external tank unit 30 may be mechanicallyconnected to the external tank unit 30 via an air hose 11. In addition,the external tank unit 30 may be electrically connected to thecompressor unit 10 via a power cord 11.

An air-compressing device 14 may be disposed within the compressor unit10 and may be driven by an electric motor 13 that serves as a drivesource for the compressor unit 10. A control circuit 15 may control theoperation of the electric motor 13. A main battery or an internalbattery 16 may supply electric power to the electric motor 13. Thecompressor unit 10 may include a power switch 22, so that electric powermay be supplied from the internal battery 16 to the electric motor 13when the power switch 22 is switched on. The internal battery 16 can beremoved from the compressor unit 10 for recharging by a charger (notshown) provided separately from the compressor unit 10, so that theinternal battery 16 can be used repeatedly.

The compressor unit 10 may further include a power input terminal 23.The electric cord 12 can be connected to the power input terminal 23, sothat external power can be supplied to a power source circuit of thecontrol circuit 15 via the electric cord 12. It may be possible to drivethe electric motor 13 also by the external power. In this embodiment, anexternal battery 37 provided at the external tank unit 30 can be used tosupply external power.

The compressed air produced by the air-compressing device 14 may bestored in a storage tank 17. A pressure sensor 18 may detect thepressure of the compressed air stored in the storage tank 17 and mayoutput a detection signal that may be input to the control circuit 15.When the pressure of the compressed air within the storage tank 17becomes lower than a predetermined value, the control circuit 15 mayoutput a control signal to the electric motor 13, so that the storagetank 17 can be replenished with compressed air.

The compressed air stored within the storage tank 17 may be regulated toa given pressure by a pressure regulator 19. The compressed air havingthe regulated pressure may be discharged from an air coupler 20 thatserves as an air outlet of the compressor unit 10. A pressure gauge 21may detect the pressure of the compressed air discharged from the aircoupler 20. The pressure gauge 21 may have a display that can displaythe detected pressure. The compressed air discharged from the air couple20 may be supplied to the external tank unit 30 via the air hose 11 thatis connected to the air coupler 20.

The external tank unit 30 serves as an auxiliary tank unit for storingthe compressed air produced by the air compressing device 14 and forsupplying the compressed air to a pneumatic tool T. The external tankunit 30 may have an air coupler 34 that can be connected to the air hose11. The compressed air supplied from the compressor unit 10 to theexternal tank unit 30 via the air hose 11 may be stored in a storagetank 32. The compressed air stored in the storage tank 32 may beregulated to a given pressure by a pressure regulator 33 and may then bedischarged from the external tank unit 30 via an air coupler 34. The aircoupler 34 may be connected to the pneumatic tool T via an air hose, sothat the compressed air discharged from the external tank unit 30 may besupplied to the pneumatic tool T. A pressure gauge 35 may detect thepressure of the compressed air discharged from the air coupler 34. Thepressure gauge 35 may have a display that can display the detectedpressure. The pneumatic tool T may be a nailer, a tacker or any othertool that may be driven by the compressed air.

The electric power of the external battery 37 of the external tank unit30 may be supplied to the compressor unit 10 via a power output terminal38 and the power cord 12. In this way, the external battery 37 can beused as a power source for the compressor unit 10. Also, the externalbattery 37 can be removed from the external tank unit 30 for rechargingby a separate charger, so that the external battery 37 can be repeatedlyused.

The control circuit 15 may monitor the residual power level of theinternal battery 16 and also the residual power level of the externalbattery 37. When the residual power level of either the internal battery16 or the external battery 37 becomes less than a given level, thecontrol circuit 15 may automatically switch the supply of electric powerto the electric motor 13 from one to the other of the batteries 16 and37.

The compressor unit 10 may be used without the external tank unit 30. Insuch a case, the external tank unit 30 may be disconnected from thecompressor unit 10. In this situation, only the internal battery 16 canbe used as a power source. The air coupler 20 may be connected directlyto the pneumatic tool T via the air hose 11. Therefore, the compressedair stored within the storage tank 17 may be directly supplied to thepneumatic tool T. If the supply of compressed air from the compressorunit 10 is insufficient, the user can connect the external tank unit 30to the compressor unit 10.

As described above, according to the air compressor 1 of the firstembodiment, the external tank unit 30 can be connected to the compressorunit 10. In this embodiment, the compressor unit 10 has the internalbattery 16 and can be used by itself (without the external tank unit30). By connecting the external tank unit 30 to the compressor unit 10,it is possible to supply a larger output of compressed air to thepneumatic tool T. In addition to or alternative to the internal battery16, the external battery 37 can be used as a power source for theelectric motor 13. Therefore, it is possible to use the air compressor 1for a long time without causing a lack of supply in electric power. As aresult, the user can efficiently perform the work using the pneumatictool T without interruption during use.

The first embodiment can be modified in various ways. For example, inthe first embodiment, the pneumatic tool T is connected to the externaltank unit 30 having the storage tank 32. In this way, the compressed airstored in the storage tank 32 can be used for driving the pneumatic toolT. Thus, the external tank unit 30 is used as an auxiliary tank for thecompressor unit 10. However, an air compressor 50 according to a secondembodiment shown in FIG. 2 is configured such that the pneumatic tool Tmay be connected to the compressor unit 10 and an external tank unit 60serving as an expansion tank may be connected to the connector body 10.

In the case of the second embodiment, the external tank unit 60 may beconnected to the storage tank 17 of the compressor unit 10 via an airhose 51. The pneumatic tool T may be connected to the air coupler 20 ofthe compressor unit 10. In another aspect, the compressor unit 10 may beconfigured to be the same as that of the first embodiment. Therefore, inFIG. 2, like members are given the same reference numerals as the firstembodiment and the description of these members will not be repeated.

The external tank unit 60 of the second embodiment may be substantiallythe same as the external tank 30 of the first embodiment except that theexternal tank unit 60 does not include the pressure regulator 33, theair coupler 34 and the pressure gauge 35. The external tank unit 60 mayinclude an air coupler 61 for connection with an air hose 51 and mayfurther include a power output terminal 62 for connection with the powercord 12.

One end of the air hose 51 may be connected to the storage tank 17 ofthe compressor unit 10 via an air coupler (not shown). The other end ofthe air hose 51 may be connected to a storage tank 63 of the externaltank unit 60 via the air coupler 61, In this way, the storage tank 17 ofthe compressor unit 10 and the storage tank 63 of the external tank unit60 may be connected to each other via the air hose 51. Therefore, thecompressed air produced at the air-compressing device 14 of thecompressor unit 10 may be stored in both the storage tank 17 of thecompressor unit 10 and the storage tank 63 of the external tank unit 60.

The external tank unit 60 may have an external battery 64 connected tothe power output terminal 62, so that electric power can be suppliedfrom the external battery 64 to the compressor unit 10 via the powercord 12. The external battery 64 may be removed from the external tankunit 60 for recharging by a charger, so that the external battery 64 canbe repeatedly used.

With the air compressor 50 according to the second embodiment, theexternal tank unit 60 can be connected to the compressor unit 10. Thecompressor unit 10 has the internal battery 16 and can be used by itself(without the external tank unit 60). By connecting the external tankunit 60 to the compressor unit 10, it is possible to supply a largeroutput of compressed air to the pneumatic tool T. In addition to oralternative to the internal battery 16, the external battery 64 can beused as a power source for the electric motor 13. Therefore, it ispossible to use the air compressor 50 during a long time without causinga lack of supply in electric power. As a result, the user canefficiently perform work using the pneumatic tool T without anysignificant interruption.

As described above, in the case of the second embodiment, the pneumatictool T may be directly connected to the compressor unit 10. Therefore,the external tank unit 60 serves as an expansion unit for supplementingthe storage capacity of the storage tank 17.

The second embodiment may be further modified. FIG. 3 shows an aircompressor including an external tank unit 70 according to a thirdembodiment. The external tank unit 70 is a modification of the externaltank unit 30 of the first embodiment and may be used in combination withthe compressor unit 10 as described in the first embodiment.

The external tank unit 30 of the first embodiment has the externalbattery 37 that can be removed for recharging by a charger that may beprovided separately from the external tank unit 30. In contrast, theexternal tank unit 70 of the third embodiment includes a charger 39 thatcan recharge the external battery 37. Therefore, it is not necessary toremove the external battery 37 for the purpose of recharging. In thisway, it is possible to improve the operability of the air compressor.The charger 39 may be connected to an external AC power source, such asan electric outlet (not shown), via a suitable connector.

In addition, as shown in FIG. 3, the external tank unit 70 may have anadditional power output terminal 40. An external electric device K maybe connected to the additional power output terminal 40. In this way,the external battery 37 can be used as a DC power source for theexternal electric device K. Therefore, it is possible to further improvethe usability of the external tank unit 70 and the air compressor 1. Theexternal electric device K may be lighting equipment, AV equipment suchas a radio or a television, cooking equipment such as a coffee maker oran electric pot, a dust collector, a fan, a blower or any other electricdevice.

The above embodiments may be further modified. For example, an AC powersource may be use for the compressor unit 10 in place of the internalbattery 16.

The storage tank 17 may be omitted from the compressor unit 10. In thecase that the storage tank 17 is omitted from the compressor unit 10 inthe first embodiment or the third embodiment, the entire amount ofcompressed air produced by the air-compressing device 14 may be storedin the storage tank 32 of the external tank unit 30. The compressed airis supplied from the air-compressing device 14 to the storage tank 32via the air hose 11. In the case that the storage tank 17 is omittedfrom the compressor unit 10 in the second embodiment, the compressed airproduced at the air-compressing device 14 may be initially stored in thestorage tank 63 of the external tank unit 60 and then may be supplied tothe pneumatic tool T via the compressor unit 10 when needed.

Further, in the above embodiments, when the residual power level ofeither the internal battery 16 or the external battery 37 becomes lessthan a given level, the control circuit 15 may automatically switch thesupply of electric power to the electric motor 13 from one to the otherof the batteries 16 and 37. However, the user may manually switch thesupply of electric power themselves. In addition, in some cases, it maybe possible to configure the compressor unit 10 such that the internalbattery 16 and the external battery 37 may be simultaneously used aspower sources.

As noted above, an AC power source may be use for the compressor unit 10in place of the internal battery 16. In the case that an AC power sourceis used, the external battery 37 of the external tank unit 30 (60, 70)may be used as an auxiliary power source in the event that the supply ofthe AC power is interrupted because of the power outage or some otherreason.

Further, the compressor unit 10 without the storage tank 17 can be usedby itself when the external tank 30 is disconnected. In such a case, thecompressed air produced by the air-compressing device 14 may be directlysupplied to the pneumatic tool T via the air hose 11. In this case, asufficient output of compressed air can be supplied to the pneumatictool T as long as the pneumatic tool T is used for a relatively lightduty work.

What is claimed is:
 1. An air compressor comprising: a compressor unitconfigured to supply compressed air to a pneumatic tool; and an externaltank unit connectible with the compressor unit; wherein the externaltank unit includes: an external tank capable of storing the compressedair; and a first battery configured to supply electric power to thecompressor unit.
 2. The air compressor according to claim 1, wherein thecompressor unit includes an air-compressing device and a second batteryserving as a power source for driving the air-compressing device.
 3. Theair compressor according to claim 2, wherein the first battery and thesecond battery can be used interchangeably for supplying electric powerto the air-compressing device.
 4. The air compressor according to claim1, wherein the external tank unit includes a battery charger capable ofcharging the first battery.
 5. The air compressor according to claim 1,wherein the external tank unit is configured to be able to connect anelectric device that is a different device from the compressor unit, sothat electric power can be supplied from the first battery to theelectric device.
 6. The air compressor according to claim 1, wherein thefirst battery is removably mounted to the external tank unit.
 7. Acompressor unit used for a pneumatic tool and connectible with anexternal tank unit having a first storage tank and a first battery, thecompressor unit comprising: an air-compressing device configured to beelectrically driven; a second battery serving as a power source fordriving the air-compressing device; a second storage tank capable ofstoring compressed air; an input terminal electrically connected to theair-compressing device and connectible with the first battery of theexternal tank unit, so that the air-compressing device can be driven byelectric power supplied from the first battery of the external tank; andan air coupler connectible with the external tank, so that compressedair produced by the air-compressing device can be stored in both thefirst storage tank of the external tank unit and the second storage tankof the compressor unit for driving a pneumatic tool.
 8. The compressorunit according to claim 7, wherein the air coupler is also connectiblewith the pneumatic tool.
 9. An external tank unit connectible with acompressor unit used for a pneumatic tool, comprising: a storage tankconfigured to store compressed air produced by the compressor unit; anda battery configured to supply electric power to the compressor unit.10. The external tank unit according to claim 9, wherein the externaltank unit further includes an air coupler connectible with a pneumatictool.